Personally I don't consider them "hidden costs" though. As its not like Disney is hiding they are charging for such services, its outlined right in plain view. Its just people aren't diligent enough to look and complain when they realize they'll be charged.
Also people for years complained about the Parks being crowded. Ok, so Disney did something about it, they raised the ticket prices which lowered crowds. In order to offset the loss of revenue due to less guests in the Parks they increased prices on other goods and services around the Parks to maintain profit. It’s simple economics. The problem is many aren't taught proper economics anymore, or don't think it applies to them. So if you want lower prices then you can't expect a less crowded Park with low wait times. And if you want a less crowded Park then you can't expect that prices for goods and services to remain low or free. Disney will always find a way to maintain profits, as any good business should do.